Dual-band Selective Double Cross Polarization for Heteronuclear Polarization Transfer between Dilute Spins in Solid-State MAS NMR
Publication year: 2012
Source: Journal of Magnetic Resonance, Available online 5 March 2012
Zhengfeng*Zhang, Yimin*Miao, Xiaoli*Liu, Jun*Yang, Conggang*Li, ...
A sinusoidal modulation scheme is described for selective heteronuclear polarization transfer between two dilute spins in double cross polarization magic-angle-spinning nuclear magnetic resonance spectroscopy. During the second N->C cross polarization, theC RF amplitude is modulated sinusoidally while theN RF amplitude is tangent. This modulation induces an effective spin-lock field in two selective frequency bands in either side of theC RF carrier frequency, allowing for simultaneous polarization transfers fromN toC in those two selective frequency bands. It is shown by experiments and simulations that this sinusoidal modulation allows one to selectively polarize fromN to its covalently bondedC? andC’ carbons in neighboring peptide planes simultaneously, which is useful for establishing the backbone connectivity between two sequential residues in protein structural elucidation. The selectivity and efficiency were experimentally demonstrated on a uniformlyC,N-labeled ?1 immunoglobulin binding domain of protein G (GB1).
Highlights
? Sine modulation was proposed for dual-band selective DCP experiments. ? Dual-band selective DCP experiments used less RF power for better selectivity. ? Dual-band selective DCP experiments were insensitive to the RF variation. ? NCO / NCA spectra of GB1 were obtained simultaneously in a single experiment.
Source:
Journal of Magnetic Resonance